Recent developments in light alloys

This report is intended to cover the progress that has been made in both the manufacture and utility of light alloys in the United States since the first part of 1919. Duralumin is extensively discussed both as to manufacture and durability

Effect of inflow control on inlet noise of a cut-on fan

The control of turbulence and other inflow disturbances in anechoic chambers for static turbofan noise studies was studied. A cut-on, high tip speed fan stage was acoustically tested with three configurations of an inflow control device in an anechoic chamber. Although this was a cut-on design, rotor inflow interaction appeared to be a much stronger source of blade passing tone radiated from the inlet than rotor stator interaction for the 1.6 mean rotor chord separation. Aft external suction applied to the area where the inflow control device joined the inlet produced a further reduction in blade passing tone, suggesting that disturbances in the forward flow on the outside of the inlet were superimposed on the inlet boundary layer and were a significant source of tone noise

A comparison of minimum distance and maximum likelihood techniques for proportion estimation

The estimation of mixing proportions P sub 1, P sub 2,...P sub m in the mixture density f(x) = the sum of the series P sub i F sub i(X) with i = 1 to M is often encountered in agricultural remote sensing problems in which case the p sub i's usually represent crop proportions. In these remote sensing applications, component densities f sub i(x) have typically been assumed to be normally distributed, and parameter estimation has been accomplished using maximum likelihood (ML) techniques. Minimum distance (MD) estimation is examined as an alternative to ML where, in this investigation, both procedures are based upon normal components. Results indicate that ML techniques are superior to MD when component distributions actually are normal, while MD estimation provides better estimates than ML under symmetric departures from normality. When component distributions are not symmetric, however, it is seen that neither of these normal based techniques provides satisfactory results

Aerodynamic and acoustic effects of eliminating core swirl from a full scale 1.6 stage pressure ratio fan (QF-5A)

Fan QF-5A was a modification of fan QF-5 which had an additional core stator and adjusted support struts to turn the core exit flow from a 30 deg swirl to the axial direction. This modification was necessary to eliminate the impingement of the swirling core flow on the axial support pylon of the NASA-Lewis Quiet Fan Facility that caused aerodynamic, acoustic and structural problems with the original fan stage at fan speeds greater than 85 percent of design. The redesigned fan QF-5A did obtain the design bypass ratio with an increased core airflow suggesting that the flow problem was resolved. Acoustically, the redesigned stage showed a low frequency broadband noise reduction compared to the results for fan QF-5 at similar operating conditions

Acoustic and aerodynamic performance of a variable-pitch 1.83-meter-(6-ft) diameter 1.20-pressure-ratio fan stage (QF-9)

Far field noise data and related aerodynamic performance are presented for a variable pitch fan stage having characteristics suitable for low noise, STOL engine application. However, no acoustic suppression material was used in the flow passages. The fan was externally driven by an electric motor. Tests were made at several forward thrust rotor blade pitch angles and one for reverse thrust. Fan speed was varied from 60 to 120 percent of takeoff (design) speed, and exhaust nozzles having areas 92 to 105 percent of design were tested. The fan noise level was at a minimum at the design rotor blade pitch angles of 64 deg for takeoff thrust and at 57 deg for approach (50 percent takeoff thrust). Perceived noise along a 152.4-m sideline reached 100.1 PNdb for the takeoff (design) configuration for a stage pressure ratio of 1.17 and thrust of 57,600 N. For reverse thrust the PNL values were 4 to 5 PNdb above the takeoff values at comparable fan speeds

Low flight speed acoustic results for a supersonic inlet with auxiliary inlet doors

A model supersonic inlet with auxiliary inlet doors and bounday layer bleeds was acoustically tested in simulated low speed flight up to Mach 0.2 in the NASA Lewis 9x15 Anechoic Wind Tunnel and statically in the NASA Lewis Anechoic Chamber. A JT8D refan model was used as the noise source. Data were also taken for a CTOL inlet and for an annular inlet with simulated centerbody support struts. Inlet operation with open auxiliary doors increased the blade passage tone by about 10 dB relative to the closed door configuration although noise radiation was primarily through the main inlet rather than the doors. Numerous strong spikes in the noise spectra were associated with the bleed system, and were strongly affected by the centerbody location. The supersonic inlet appeared to suppress multiple pure tone (MPT) generation at the fan source. Inlet length and the presence of support struts were shown not to cause this MPT suppression

Bulletin No. 262 - Comparative Yields of Spring Wheat Varieties in Utah

Wheat was one of the first crops grown by early Utah settlers. It has since occupied an important place in the agriculture of the state. While wheat is almost the only crop grown successfully on dry-lands, it is also important under irrigation. Thirty per cent of the wheat acreage of Utah in 1929 was spring-sown, which produced 44 per cent of the state\u27s production. Eighty-seven per cent of the spring wheat acreage was grown under irrigation, this acreage producing 92.3 per cent of the total spring wheat crop. Thirty-eight per cent of Utah farmers were growing spring wheat in 1929; this wheat was grown in all ,counties of the state except one, the percentage of farmers growing this crop at that time ranging from less than 1 per cent in Washington and San Juan Counties to 64 per cent in Emery County; yet Emery County ranks about sixth in acreage and eighth in production

Bulletin No. 263 - Relative Produciton of Feed Grain from Spring-Grown Cereals in Utah

Nearly one-third of the cropped acreage of Utah is devoted to cereals. Except for wheat, most of these crops are fed locally. In addition to this, an average of over a million bushels of corn, barley, and oats is shipped into the state each year to be used in various livestock and poultry industries. The purpose of this publication is to show the comparative amount of feed produced by the different crops--wheat, oats, barley, and corn--under similar conditions as determined for the specified four years by acre-yields obtained in various agricultural regions of the state. One should bear clearly in mind that its purpose is not to encourage all farmers to grow crops giving the highest feed value to the acre or to shift from one cereal to another, although this might be done to advantage if increased feed production is desired

Bulletin No. 293 - Velvon: A New Smooth-Awned Barley

Velvon, a new barley variety with smooth awns, with relatively stiff straw, and with a high degree of resistance to covered smut was developed at the Utah Agricultural Experiment Station through the cooperative efforts of the Station and the Division of Cereal Crops and Diseases, Bureau of Plant Industry, U. S. Department of Agriculture. This new variety resulted as a hybrid strain from a cross made in 1930 for the purpose of improving straw strength and the texture of awns